Good advice from sbank and shakey.
A Cardas set up is a good place to start with your speaker. Variations in recommendations are permissible. Don't get too anal.:-)
Your room has an inherent problem dimension wise, and that is the multiples, i.e. 16x2 = 32 and 8x16 &32 are multiples. This can cause substantial nulls and nodes in your room which can make the lower mids down thru the bass seem either boomy or thin. These can be difficult to tame but a lot of headway can be made by close attention to listening chair and speaker placement. Inches can matter a whole lot. It really helps if you have a sound pressure level meter and an audio frequency test disc so you can measure the SPL at various frequencies at the listening position and make adjustments. I would do this BEFORE I tried to tame or change the room itself by using absorbers/reflectors/traps etc which IMHO should only be used to fine tune after you have identified and understand the room and have found the best positions of the speakers and listening seat. This is not a quick fix however, it takes a lot of time and attention to detail! I would also recommend that you resist the recommendations to buy equipment until you figure out your best set up. Compared to room/set up issues, equipment changes are minor and will just have you chasing your tail! :-)
BTW, do not overlook toe in issues, including using that to minimize first reflection points.
Good luck with your project. Been there, done that, and it probably took me over a year to really get it done right.
